The invention relates to a vacuum valve comprising a wall with a valve opening and a valve seat that surrounds the valve opening and that has a sealing surface lying in a plane or a sealing ring lying in a plane and a valve plate that can be adjusted over a closing path from an open position, in which it frees the valve opening, into a closed position, in which it closes the valve opening, wherein this valve plate has a sealing ring that is pressed onto the sealing surface of the valve seat in the closed position or a sealing surface on which the sealing ring of the valve seat is pressed in the closed position, wherein the valve plate is moved, during the closing of the vacuum valve starting from the open position of the valve plate, over a main section of the closing path in a main closing direction that is parallel to the valve plate and that is parallel to the plane of the sealing surface or the sealing ring of the valve seat and is then moved, following the main section of the closing path, over a final section of the closing path running at an angle to the valve plate and at an angle to the plane of the sealing surface or the sealing ring of the valve seat for guiding the valve plate onto the valve seat.
Vacuum valves according to a type of plate valves in which the valve opening is closed by a valve plate that is pressed against the valve seat surrounding the valve opening have become known in many different embodiments. Here, in order to expose the seal formed of an elastic material to shear loading that is not too strong, it is known to perform the closing movement of the valve plate in two stages. In a first section of the closing path that comprises a large part of the extent of the closing path, the valve plate is moved from an open position freeing the valve opening into an intermediate position covering the valve opening but still lifted from the valve seat. In the final section of the closing path, the valve plate is moved from the intermediate position into the closed position in which it is pressed onto the valve seat and seals the valve opening.
In the case of a conventional type of slide valves, this two-stage movement process of the valve plate is caused by mechanical elements that are arranged between a carrier plate moved by at least one actuator and the valve plate. These mechanical elements can involve roller bodies that are guided in wedge-shaped columns between the valve plate and the carrier plate, lever mechanisms or rocking elements between these two plates. In order to avoid or limit bending of the valve rod during the second movement step, the carrier plate or a similar support plate connected to the support plate by mechanical elements used for spreading is supported against a wall of the valve housing opposite the valve seat. Such slide valves are known, for example, from U.S. Pat. No. 4,560,141 A, DE 3 209 217 C2, DE 3224387 C2, and U.S. Pat. No. 3,185,435 A.
Furthermore, the second section of the closing movement can be achieved by pivoting the valve rod about an axis lying at a right angle to the valve rod. This pivoting of the valve rod can be achieved, for example, by a connecting rod guide, compare, e.g., U.S. Pat. No. 7,066,443 B2, or by use of separate actuators, compare, e.g., U.S. Pat. No. 7,059,583 B2, U.S. Pat. No. 6,390,448 B1, or DE 19 633 798 A1.
Furthermore, it is known to construct the second section of the closing movement such that the valve plate can be moved relative to a carrier plate through the use of at least one actuator, wherein this carrier plate can be moved over the first section of the closing path by the at least one actuator. Such vacuum valves are known, for example, from U.S. Pat. No. 6,056,266 and U.S. Pat. No. 6,899,316 B2.
Furthermore, from U.S. Pat. No. 6,776,394 B2, a so-called pendulum valve is known in which, in the first step, the valve plate is shifted not in a linear way, but instead is pivoted along a circular arc. In order to achieve a sufficient contact force of the valve plate on the valve seat, tappets that can move in the valve housing are provided here with which the valve plate can be pressed onto the valve seat. From US 2007/0 228 314 A1, a pendulum valve emerges in which the movable tappets are supported in the valve plate and supported on the housing.
For a different type of plate valves or slide valves, the sealing surface and the sealing ring are constructed three-dimensionally such that during the straight-line travel of the valve plate into the valve seat, no shear loads act on the elastomer seal. The valve plate is shifted in a straight line over its entire closing path from its open position into its closed position. Such a valve is known, for example, from U.S. Pat. No. 4,921,213.
It has further become known to arrange two closing elements that can be activated independently from each other in a common valve housing, wherein a first valve opening can be sealed by the first closing element and a second valve opening can be sealed by the second closing element.
Plate valves in which, in the first section of the closing movement, the valve plate is shifted linear to the plane of the valve seat and is shifted in the final section of the closing movement essentially perpendicular to the valve seat and is pressed onto this valve seat, are also designated as L-valves. If, in the final section of the closing movement, the movement is realized at an angle to the direction of movement of the first step and to the plane of the valve seat, then the designation J-valve is also used.